Image stabilization device for a camera

What is claimed is:

1. An image stabilization device including:

(A) image processing means for receiving a light beam from an object and utilizing the beam as image information;

(B) blur correcting means for driving an imaging system to correct blurring of an image;

(C) initial setting means for setting said imaging system to an initial state for driving of said blur correcting means; and

(D) interlocking control means for inhibiting a simultaneous operation of said image processing means and said initial setting means.

2. A device according to claim 1, wherein said image processing means includes automatic focus detecting means for performing a focus detection operation.

3. A device according to claim 1, wherein said image processing means includes an exposing means for performing an exposure operation.

4. An image stabilizing device according to claim 1, wherein said imaging system includes a lens.

5. An image stabilizing device according to claim 1, wherein said initial setting means includes means for placing said imaging system at a center of an operation range thereof.

6. An image stabilizing device according to claim 1, wherein said interlocking control means includes priority means for establishing a higher priority of operation to said image processing means than to said initial setting means.

7. An image stabilizing device according to claim 6, wherein said priority means includes means for prohibiting an operation of said initial setting means when said image processing means starts to operate.

8. An image stabilizing device according to claim 6, wherein said priority means includes means for starting an operation of said image setting means when said image processing means is in operation.

9. An image stabilizing device according to claim 6, wherein said interlocking control means includes means for automatically starting the operation of said initial setting means after completion of an operation of said image processing means.

10. An image stabilizing device according to claim 6, wherein said priority means includes means for prohibiting an operation of said image processing means when said initial setting means begins to operate.

11. An image stabilizing device according to claim 6, wherein said priority means includes means for starting an operation of said image setting means when said initial setting means is in operation.

12. An image stabilizing device according to claim 6, wherein said interlocking control means includes means for automatically starting the operation of said image processing means after completion of the operation of said initial setting means.

13. An image stabilizing device according to claim 1, wherein said interlocking control means includes priority means for establishing a higher priority of operation to said initial setting means than to said image processing means.

14. An image stabilizing device according to claim 1, further comprising means for prohibiting the operation of said interlocking means at an initial operation stage of said image processing means.

15. An image stabilizing device according to claim 1, wherein said interlocking control means includes means for prohibiting the operation of said initial setting means when said image processing means accumulates light flux from the object.

16. An image stabilizing device according to claim 1, wherein said interlocking control means includes means for prohibiting said image processing means from accumulating light flux from the object.

17. A camera including:

(A) image processing means for receiving a light beam from an object and utilizing the beam as image information;

(B) blur correcting means for driving an imaging system to correct blurring of an image;

(C) initial setting means for setting said imaging system to an initial state for driving said blur correcting means; and

(D) interlocking control means for inhibiting a simultaneous operation of said image processing means and said initial setting means.

18. A camera according to claim 17, wherein said image processing means includes automatic focus detecting means for performing a focus detection operation.

19. A camera according to claim 17, wherein said image processing means includes an exposing means for performing an exposure operation.

20. A camera according to claim 17, wherein said imaging system includes a lens.

21. A camera according to claim 17, wherein said initial setting means includes means for placing said imaging system at a center of an operation range thereof.

22. A camera according to claim 17, wherein said interlocking control means includes priority means for establishing a higher priority of operation to said image processing means than said initial setting means.

23. A camera according to claim 22, wherein said priority means includes means for prohibiting an operation of said initial setting means when said image processing means starts to operate during said initial setting means in operation.

24. A camera according to claim 22, wherein said priority means includes means for starting an operation of said image setting means when said image processing means is being in operation.

25. A camera according to claim 22, wherein said interlocking control means includes means for automatically starting the operation of said initial setting means after completion of an operation of said image processing means.

26. A camera according to claim 22, wherein said priority means includes means for prohibiting an operation of said image processing means when said initial setting means beginning to operate.

27. A camera according to claim 22, wherein said priority means includes means for starting an operation of said image setting means when said initial setting means is in operation.

28. A camera according to claim 22, wherein said interlocking control means includes means for automatically starting the operation of said image processing means after completion of the operation of said initial setting means.

29. A camera according to claim 17, wherein said interlocking control means includes priority means for establishing a higher priority of operation to said initial setting means than to said image processing means.

30. A camera according to claim 17, further comprising means for prohibiting the operation of said interlocking means at an initial operation stage of said image processing means.

31. A camera according to claim 17, wherein said interlocking control means includes means for prohibiting the operation of said initial setting means when said image processing means accumulates light flux from the object.

32. A camera according to claim 17, wherein said interlocking control means includes means for prohibiting said image processing means from accumulating the light flux from the object.

33. An optical apparatus including:

(A) image processing means for receiving a light beam from an object and utilizing the beam as image information;

(B) blur correcting means for driving an imaging system to correct blurring of an image;

(C) initial setting means for setting said imaging system to an initial state for driving said blur correcting means; and

(D) interlocking control means for inhibiting a simultaneous operation of said image processing means and said initial setting means.

34. An optical apparatus according to claim 33, wherein said image processing means includes automatic focus detecting means for performing a focus detection operation.

35. An optical apparatus according to claim 33, wherein said image processing means includes an exposing means for performing an exposure operation.

36. An optical apparatus according to claim 33, wherein said imaging system includes a lens.

37. An optical apparatus according to claim 33, wherein said initial setting means includes means for placing said imaging system at a center of an operation range thereof.

38. An optical apparatus according to claim 33, wherein said interlocking control means includes priority means for establishing a higher priority of operation to said image processing means than to said initial setting means.

39. An optical apparatus according to claim 38, wherein said priority means includes means for prohibiting an operation of said initial setting means when said image processing means starts to operate.

40. An optical apparatus according to claim 38, wherein said priority means includes means for starting an operation of said image setting means when said image processing means is in operation.

41. An optical apparatus according to claim 38, wherein said interlocking control means includes means for automatically starting the operation of said initial setting means after completion of an operation of said image processing means.

42. An optical apparatus according to claim 38, wherein said priority means includes means for prohibiting an operation of said image processing means when said initial setting means beginning to operate.

43. An optical apparatus according to claim 38, wherein said priority means includes means for starting an operation of said image setting means when said initial setting means is in operation.

44. An optical apparatus according to claim 38, wherein said interlocking control means includes means for automatically starting the operation of said image processing means after completion of the operation of said initial setting means.

45. An optical apparatus according to claim 33, wherein said interlocking control means includes priority means for establishing a higher priority of operation to said initial setting means than to said image processing means.

46. An optical apparatus according to claim 33, further comprising means for prohibiting the operation of said interlocking means at an initial operation stage of said image processing means.

47. An optical apparatus according to claim 33, wherein said interlocking control means includes means for prohibiting the operation of said initial setting means when said image processing means accumulates light flux from the object.

48. An optical apparatus according to claim 33, wherein said interlocking control means includes means for prohibiting said image processing means from accumulating the light flux from the object.

Description Submit all comments and votes

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image stabilization device for a camera, wherein image displacement caused by a camera-shake due to hand trembling can be eliminated by driving an imaging system such as an optical system.

2. Related Background Art

Various conventional image stabilization devices have been proposed. In such a device, an image displacement on an imaging surface of e.g., a film due to camera-shake caused by a hand trembling or the like, is suppressed such that a lens system as an object to be controlled is driven in a vibration suppression direction.

For example, a camera vibration (normally, a camera vibration with respect to a photographing optical axis) is detected as an acceleration signal, and this acceleration signal is integrated by a signal processing system to obtain a displacement signal (or a velocity signal). The lens system is driven by these signals in a lens vibration suppression vibration of an image).

FIG. 18 is a diagram of a typical arrangement showing a principle of an image stabilization device including a conventional signal processing system of the type described above. An accelerometer (Rot Acc) 1 detects a camera (not shown) vibration with respect to a photographing optical axis as an acceleration signal. A detected acceleration signal a is integrated into a velocity signal v by a first integrator 2. The velocity signal v is then converted into a displacement signal d by a second integrator 3.

An actuator 5 is operated to drive a radially displaceable camera imaging system 4 (normally, an imaging lens system) in the radial direction to achieve image stabilization in accordance with the displacement signal d.

A variable resistor 6 constitutes a position detecting means for detecting an actual positional displacement of the imaging system 4. A signal from this position detecting means is fed back to an input system of the actuator, thereby constituting a feedback loop for matching radial position of the imaging system 4 with the vibration displacement.

A spring 8 urges the imaging system 4 toward a one-side limit position of its movable range during inactivation of the actuator 5. Unnecessary movement of the imaging system 4 during inactivation of the actuator 5 is thus prevented.

In the conventional arrangement described above, a radial position of the imaging system 4 upon activation of the actuator 5 is determined by a balance between the spring force of the spring 8 and a driving force generated by the actuator 5. In order to optimize an image stabilization start operation, an imaging system centering means as an initial position setting means is generally provided due to the presence of the spring 8.

The above operation will be briefly described. An overall radial stroke of the imaging system 4 in the above arrangement is defined as l, and an origin is defined as a central position (i.e., an /2 position) of the imaging system 4. Then, the imaging system 4 is urged at the -l/2 position by the spring 8 during inactivation of the actuator 5. When the actuator 5 is activated, the imaging system 4 must start an image stabilization operation while being kept urged at the -l/2 position if the centering means is not arranged. As the imaging system 4 is located at a negative limit position, it cannot be further moved in the negative direction. Therefore, a good image stabilization effect cannot be expected.

In order to arbitrarily move the imaging system in the positive or negative direction upon activation of the actuator 5, the imaging system centering means is added to immediately move the imaging system 4 from the -l/2 position to the origin at the activation start timing of the actuator 5 (This operation is called a centering operation). Image stabilization is started after the centering operation by the imaging system centering means is completed. A centering operation time is ideally almost zero. However, in practice, the centering time is about 30 to 100 msec due to an operating time of the imaging system 4 and a vibration damping time after centering.

The centering operation is utilized not only at the start of actuator operation but also during image stabilization control as needed. That is, the stroke of the actuator 5 and outputs from the integrators 2 and 3 are not infinite, and the imaging system may be moved to the stroke limit position within the camera (lens barrel) due to large vibrations. In this case, when the outputs from the integrators 2 and 3 are reset to re-start the centering operation of the imaging system, subsequent image stabilization control can be optimized.

In recent years, most of the commercially available cameras incorporate AF (Auto Focus) units for automatically focusing an image so as to reduce, for example, a load from a photographer. An application of the image stabilization device to an AF camera poses some problems. Prior to a description of these problems, an AF unit will be generally described.

Various types of AF unit are available. A single-lens reflex camera having many interchangeable lenses employs a TTL passive AF unit to cope with focal lengths of various interchangeable lenses from a wide angle lens to a telephoto lens. FIGS. 19(a) to 19(c) show operating states of such a TTL passive AF unit. This AF unit includes a field lens 11 located on an optically equivalent plane to a film surface as a primary imaging plane, a photographing lens 27, and secondary imaging lenses 13a and 13b. Two beams passing through different areas of the photographing lens 27 are independently sampled, and space images formed on the primary imaging plane are formed on distance measuring sensors 14a and 14b again. Each distance measuring sensor comprises a line photoelectric transducer element such as a BASIS or a CCD. Automatic gain control (AGC) for adjusting the photographing condition to the brightness of external light is generally performed by changing an accumulation time of the photoelectric transducer element.

In this AF unit, an in-focus state (FIGS. 19(a) and 20(a)), a forward focus state (FIGS. 19(b) and 20(b)), and a backward focus state (FIGS. 19(c) and 20(c)) are detected in accordance with distances between the object images on the distance measuring sensors 14a and 14b. A photographing lens drive mechanism (not shown) is driven in accordance with the detected state, and automatic focusing or focus adjustment can be achieved.

A camera with a telephoto lens is inevitably vibrated by the operator's hands or even if a tripod is used due to wind. This problem also occurs even in a camera having an AF unit. It is therefore also effective to mount an image stabilization device in the AF camera.

The following problem is posed when the image stabilization device and the AF unit as independent components are mounted in a camera.

Assume that the imaging system is moved to perform image stabilization in the radial direction while a distance measuring operation of the AF unit is being performed. In this case, displacement of an image formed on the distance measuring sensor can be prevented to obtain a good distance measuring effect. However, in the image stabilization device for centering the imaging system to the origin at the start of image stabilization operation, if the centering operation and the distance measuring operation are simultaneously performed, an error often occurs.

A cause of this erroneous operation will be described below.

Assume that charge is accumulated by the photoelectric transducer element serving as a distance measuring sensor, and that the imaging system centering operation of the image stabilization device is being performed. Under these conditions, an object image on the distance measuring sensor is abruptly moved during the accumulating operation. For this reason, a distance measuring disable state occurs due to movement of the image, thus causing a distance measuring error.

The above problems are also presented in association with another device for detecting photographic information by using a photoelectric transducer means.

In addition, the centering operation poses a problem in association with an exposure operation of a silver chloride film or the like. That is, an image stabilization operation must be effective during film exposure. However, when the imaging system 4 is deviated from the center of the stroke and then a release operation is started, the imaging system 4 tends to abut against the stroke end on the side having a small stroke margin. Then, the image stabilization operation tends to be invalidated. For this reason, it is preferable that every time the release operation is started, the centering operation is performed to locate the imaging system 4 at the center of the stroke, and the release operation is started.

However, the centering operation requires a period of 30 to 100 msec. If the release operation is started during the centering operation, the imaging system 4 is moved independently of hand trembling while the shutter is open and the film is exposed to light. Therefore, an image which is displaced in the direction of movement of the imaging system 4 is recorded on the film surface.

SUMMARY OF THE INVENTION

The present invention has been made in consideration of the above situation, and has as its object to provide an image stabilization device comprising an automatic focus detecting means for receiving a beam from an object to use the beam as image information, image processing means such as exposing means, a displacement compensation means for driving an imaging system so as to compensate displacement of an image, initial setting means for setting the imaging system to an initial state for driving by the displacement correcting means, and interlocking control mean for preventing simultaneous driving of the image processing means and the initial setting means, wherein a problem caused by simultaneous driving of the image processing means and the initial setting means can be eliminated, and the image processing means can be optimally operated.

The above and other objects, features, and advantages of the present invention will be apparent from the following detailed description of preferred embodiments in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a circuit arrangement of a camera having an image stabilization device according to a first embodiment of the present invention;

FIG. 2 is a flowchart for explaining control procedures of a CPU in the image stabilization device shown in FIG. 1;

FIG. 3 is a block diagram showing a circuit arrangement of a camera having an image stabilization device according to a second embodiment of the present invention;

FIG. 4 is a block diagram showing a hardware arrangement of a camera according to a third embodiment of the present invention;

FIGS. 5 and 6 are flowcharts for explaining control procedures of an image stabilization device of the third embodiment;

FIG. 7 is a block diagram showing a hardware arrangement of a camera according to a fourth embodiment of the present invention;

FIG. 8 consisting of FIGS. 8A, 8B and 8C, is a flowchart for explaining control procedures of an image stabilization device according to the fourth embodiment;

FIG. 9 is a block diagram showing a circuit arrangement of a camera having an image stabilization device according to a fifth embodiment of the present invention;

FIG. 10 is a flowchart for explaining control procedures of a CPU of the image stabilization device of FIG. 9;

FIG. 11 is a block diagram showing a circuit arrangement of a camera having an image stabilization device according to a sixth embodiment of the present invention;

FIG. 12 is a block diagram showing a hardware arrangement of a camera according to a seventh embodiment of the present invention;

FIGS. 13 and 14 are flowcharts for explaining control procedures of an image stabilization device according to the seventh embodiment;

FIG. 15 is a block diagram showing a hardware arrangement of a camera according to an eighth embodiment of the present invention;

FIGS. 16 and 17 are flowcharts for explaining control procedures of an image stabilization device according to the eighth embodiment;

FIG. 18 is a diagram showing an arrangement of a conventional image stabilization device;

FIGS. 19(a) to 19(c) and FIGS. 20(a) to 20(c) are views for explaining operating states of a conventional passive AF unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

FIG. 1 is a block diagram showing an image stabilization device for a camera according to a first embodiment of the present invention. The same reference numerals as in FIGS. 18 to 19(c) denote the same parts in FIG. 1, and a detailed description thereof will be omitted.

This embodiment exemplifies a single-lens reflex camera having an AF unit.

A central position of a quick return mirror 9 is constituted by a half mirror or a pattern mirror as a combination of a total reflection portion and a transparent portion for distance measurement. Light incident on a photographing lens is partially transmitted through the quick return mirror 9 at a predetermined ratio. A sub mirror 10 guides the light passing through the quick return mirror 9 to a distance measuring optical system. The single-lens reflex camera also includes a field lens 11, a fixed aperture 12, a pair of secondary imaging lenses 13, and a pair of line photoelectric transducer elements 14 serving as distance measuring sensors.

A sensor accumulation controller 15 controls the distance measuring sensors 14. A known central processing unit (CPU.sub.1) 16 for an AF unit calculates a defocus amount on the basis of a distance measuring principle (described with reference to FIGS. 19(a) to 20(c)) using data from the distance measuring sensors 14 and performs focus adjustment upon driving of a focus adjusting driver 17.

A central processing unit (CPU.sub.2) 18 for an image stabilization device performs the centering operation upon operation of an image stabilization start switch (not shown), as shown in a flowchart of FIG. 2. The output port of a parallel I/O (interface) 19 is connected to a one-shot circuit 20. The input port of the parallel I/O 19 is connected to the Q output of an RS flip-flop 21. The one-shot circuit 20 outputs an "H" pulse when an output from the parallel I/O 19 goes high.

The set (S) input terminal of the RS flip-flop 21 is connected to the output terminal of the one-shot circuit 20. The reset (R) input terminal of the flip-flop 21 is connected to a gate circuit 22. The Q output of the flip-flop 21 is connected to the reset input terminals of the integrators 2 and 3, a gate circuit 26, and the parallel I/O 19.

The gate circuit 22 serves as a priority circuit for eliminating an unstable state (R input=S input="H") of the RS flip-flop 21 and giving a priority to the S input over the R input.

A centering reference power source 24 generates a voltage for holding the imaging system 4 at the center (origin) in the stroke range and is arranged such that a voltage as a sum of the voltage of the centering reference power source 24 and an output voltage of the integrator 3, both of which are added by an adder 23, is applied to the operational amplifier 7.

A reset circuit 25 generates a reset output (="H") when the imaging system 4 comes close to the origin The input terminal of the reset circuit 25 is connected to the position detecting means 6. The output terminal of the reset circuit 25 is connected to the R input of the RS flip-flop 21 through the gate circuit 22.

An arrangement of the reset circuit 25 will be described in detail. The reset circuit 25 includes comparators 25a and 25b. Each comparator generates an output of "H" level when an input voltage applied to the + or noninverting terminal thereof is higher than the input voltage applied to the - or inverting terminal thereof. Otherwise, the comparator generates an output of "L" level. The reset circuit 25 also includes reference power sources 25c and 25d.

If a voltage of the centering reference power source 24, a voltage of the reference power source 25c, and a voltage of the reference power source 25d are defined as V.sub.24, V.sub.c, and V.sub.d, respectively, and if the voltages V.sub.c and V.sub.d are determined to satisfy the following equation:

V.sub.24 =V.sub.c +V.sub.d /2 (1)

then an output from the reset circuit 25 is set at "H" level only when a voltage V of the position detecting means 6 falls within the following range:

V.sub.c <V<V.sub.c +V.sub.d (2)

that is, an output from the comparator 25a is set at "H" level and at the same time an output from the comparator 25b is set at "L" level.

The gate circuit 26 controls a sensor accumulation controller 15 to inhibit an accumulating operation of the distance measuring sensors 14 when a Q output from the RS flip-flop 21 is set at "H" level.

An operation of the device having the above arrangement will be described below. FIG. 2 is a flowchart showing control procedures of the CPU.sub.2 18 for the image stabilization device.

Assume that an output Q from the RS flip-flop 21 is set at "L" level, that the integrator 3 is connected to the operational amplifier 7 through the switch circuit 23, and that an image stabilization feedback system constituted by the components 1 to 8 and an automatic focus adjusting system constituted by the components 9 to 17 are rendered operative. Under these assumptions, the automatic focus adjusting system repeats the following operations:

(1) Accumulating operation of the distance measuring sensors 14;

(2) Calculation of defocus amount by using data from the distance measuring sensors 14 under the control of the CPU.sub.1 16; and

(3) Driving of the focus adjusting driver 17 on the basis of the defocus amount calculated in step (2).

Centering of the imaging system 4 in the image stabilization system will be described below.

The CPU.sub.2 18 for image stabilization detects an input from a switch (not shown) or saturation of outputs from the integrators 2 and 3 and sets an output of the parallel I/O 19 to be "H" level, thereby starting a centering operation. The one-shot circuit 20 outputs an "H" pulse when the parallel I/O 19 goes high. The RS flip-flop 21 is set in response to this "H" pulse, and a Q output from the flip-flop 21 goes high. When this output Q is set at "H" level, the integrators 2 and 3 are reset. When this output is set at "H" level, the integrators 2 and 3 are reset, and their outputs are cleared to 0. An instruction voltage applied to the operational amplifier 7 is given by only the voltage from the centering reference power source 24. For this reason, a feedback force toward a position designated by the voltage of the reference power source 24, that is, the force acting toward the origin of the imaging system 4, is applied to the components 4 to 8. This operation is called a centering operation. When the Q output from the flip-flop 21 is kept high, an accumulating operation of the distance measuring sensors 14 under the control of the sensor accumulation controller 15 is inhibited by the gate circuit 26. Therefore, distance measurement during centering can be prevented.

When the imaging system 4 comes sufficiently close to the origin as the reference position by the centering operation and the voltage V from the position detecting means 6 falls within the range given by inequality (2), an output from the reset circuit 25 goes high At the same time, the one-shot circuit 20 generates an output pulse. The Q output of the RS flip-flop 21 is reset to "L" level unless the gate circuit 22 inhibits such an operation. When the Q output is set at "L" level, reset inputs to the integrators 2 and 3 go low and a displacement signal d is output from the integrator 3. Therefore the centering operation is finished, and an image stabilization operation is started (restarted). In this case, an input to the gate circuit 26 also goes low, and accumulation inhibition of the distance measuring sensors 14 can be released.

In this embodiment, the Q output from the RS flip-flop 21 is input to the CPU.sup.2 18 for image stabilization through the parallel I/O 19 to detect an end of centering upon monitoring of a change in logic level from "H" level to "L" level of the Q output, and the output from the parallel I/O 19 is set at "L" level (FIG. 2). The centering operation of the imaging system in the image stabilization device is thus completed.

Second Embodiment

An interlocking means is arranged to inhibit the operation of the sensor accumulation controller 15 for controlling the distance measuring sensors in the AF unit during the centering operation of the image stabilization device in the first embodiment described above. In a second embodiment shown in FIG. 3, an interlocking means is arranged to inhibit a centering operation of the image stabilization device during an operation of the sensor accumulation controller 15 in the AF unit.

A circuit arrangement of the second embodiment lies in a feature wherein a set (S) input and a reset (R) input to an RS flip-flop 21 for performing the centering operation are controlled by an output (a signal S' during sensor accumulating operation) from the sensor accumulation controller 15. More specifically, the set (S) input is obtained such that the signal S' is input to a one-shot circuit 20 through a gate circuit 22'. Only when the signal S' is set at "L" level, an "H" input is applied from the one-shot circuit 20 to the S terminal of the RS flip-flop 21.

The reset (R) input is applied as an "H" input to the R terminal when either the signal S' or an output from a reset circuit 25 is set at "H" level.

In the second embodiment, a circuit for inhibiting the operation of the sensor accumulation controller 15 during the centering operation of the image stabilization device is omitted. Other arrangements of this embodiment are substantially the same as those of the first embodiment shown in FIG. 1.

With the above arrangement, the centering operation of the image stabilization device is inhibited during the accumulating operation of the distance measuring sensors in the AF unit.

An operation will be described wherein an accumulating operation of the distance measuring sensors 14 is started during a centering operation. When the accumulating operation of the distance measuring sensors 14 is started, a center accumulating signal is set at "H" level by the sensor accumulation controller 15. An output from an OR gate 26' is set at "H" level accordingly, and the RS flip-flop 21 is reset. When the RS flip-flop 21 is reset and its Q output goes low, the centering operation is forcibly interrupted, and the image stabilization operation is re-started.

Third Embodiment

FIG. 4 is a block diagram showing a third embodiment of the present invention. A read-only memory (ROM) is often arranged in each interchangeable lens barrel to adjust differences in focal lengths in an AF single-lens reflex camera, while a camera body receives lens information required for focus adjustment and exposure control calculations from the lens barrel by means of communication. In this embodiment, an accumulation inhibiting means of photoelectric transducer elements in the AF unit utilizes communication.

Referring to FIG. 4, the camera includes a camera body 31, an interchangeable lens barrel 32, and a distance measuring portion 33 including distance measuring sensors and other optical systems. The distance measuring portion 33 corresponds to the components 10 to 15 in the embodiment of FIG. 1. A CPU 34 on the camera body side (to be referred to as a body CPU 34 hereinafter) performs distance measuring operations on the basis of data from the distance measuring portion 33 by means of communication and instructs the resultant lens drive amount to a CPU 40 on the lens barrel side (to be referred to as a lens CPU 40 hereinafter). The body CPU 34 also performs known control operations associated with data display and exposure. The body CPU 34 communicates with the lens CPU 40 through interfaces 35 and 41.

An image stabilization device in this embodiment is built into a lens barrel. An aperture driver 43 and a focusing driver 42 are also built into the lens barrel. An image stabilization CPU 37 controls image stabilization of the image stabilization device and the centering operation. An interface 38 is used as an interface for the image stabilization CPU 37. An image stabilization driver 39 corresponds to the components 1 to 8 in the embodiment of FIG. 1. The device of this embodiment is arranged to disable an operation of the lens CPU 40 under the control of the image stabilization CPU 37. The interfaces 38 and 41 in the lens barrel are connected in parallel with each other and are connected to the body interface 35 through signal terminals 36a to 36c arranged in a mount. Communication is serially performed, e.g., in units of bytes. A communication system is constituted as a communication synchronization clock line 36a for supplying a clock from the body, a signal line 36b for supplying a signal from the body to the lens, a signal line 36c for supplying a signal from the lens to the body, and a ground line (not shown).

An operation of the third embodiment will be described below.

An operation will be exemplified wherein image stabilization and automatic focus adjusting operations are being performed, but a centering operation is not performed.

In an automatic focus adjusting mode, the body CPU 34 sends a transmission request command for data required for distance measuring calculations (e.g., a focal length and sensitivity of a lens) to the lens CPU 40 through the interface 35. When the lens CPU 40 receives the command through the interface 41, the requested data is transmitted to the body in synchronism with a communication clock supplied from the body. The body CPU 34 enables the distance measuring portion 33, and the accumulating operation of the distance measuring sensors in the distance measuring portion 33 is performed. Distance measuring operations are performed on the basis of lens data and data from the distance measuring portion 33. The calculation results are used to calculate a focusing drive amount for achieving an in-focus state and this amount is supplied together with a focusing drive command (e.g., 20.sub.H (H: hexadecimal notation)) to the lens CPU 40. The lens CPU 40 drives the focusing driver 42 in accordance with the received focusing drive amount. The above operations are the same as those known to a person skilled in the art. The foregoing operations are repeated to perform the automatic focus adjusting operation.

In this embodiment, the image stabilization CPU 37 monitors through the interface 38 communication between the body CPU 34 and the lens CPU 40. The image stabilization CPU 37 also monitors an integrator output in the image stabilization driver 39. The image stabilization driver 39 is arranged as an analog feedback system constituted by the components 1 to 8 of FIG. 1, and the image stabilization CPU 37 is not directly associated with a feedback loop.

A centering operation according to this embodiment will be described below.

When outputs from the integrators in the image stabilization driver 39 are saturated or the image stabilization CPU 37 receives a centering command (e.g., 30.sub.H) from the body CPU 34, the image stabilization CPU 37 performs the operations shown in a flowchart of FIG. 5. The image stabilization CPU 37 disables the lens CPU 40 and transmits a status word (e.g., 40.sub.H) representing that centering is being executed to the body CPU 34. The image stabilization CPU 37 supplies a centering operation execution signal to the image stabilization driver 39.

An operation of the body CPU 34 is shown the flowchart of FIG. 6. When the body CPU 34 receives the status word representing that centering is being executed, the body CPU 34 inhibits an accumulating operation of the distance measuring sensors in the distance measuring portion 33.

When the centering operation is completed, the image stabilization driver 39 automatically restarts an image stabilization operation, and the image stabilization CPU 37 transmits a status word (e.g., 50.sub.h) representing finishing of centering operation to the body CPU 34. At the same time, a disable state of the lens CPU 40 is cancelled.

When the CPU 34 receives the status word representing the finishing of centering operation, it releases inhibition of the accumulating operation of the distance measuring sensors and allows to an automatic focus adjusting operation restart.

The centering operation of the image stabilization device has a priority over a series of control operations of the AF unit. Therefore, simultaneous operations are inhibited, and a fail-safe AF operation can be assured.

In this embodiment, the image stabilization CPU 37 transmits to the body CPU 34 the status code representing that centering is being executed, thereby inhibiting the accumulating operation of the distance measuring sensors. However, the following arrangement may be alternatively employed. That is, when a lens communication and an accumulating operation of the distance measuring sensors are not simultaneously performed in the body sequence but may be serially performed and a hand shake line is provided to signal an end of communication preparation from the lens CPU to the body CPU (the hand shake line may be constituted by the synchronization clock line 36a), the image stabilization CPU 37 uses a means for forcibly setting the hand shake line in a communication disable state during centering to inhibit communication between the lens CPU and the body CPU. In this case, the body CPU is set in a communication wait state with respect to the lens CPU, and therefore the accumulating operation of the distance measuring sensors can be inhibited during centering. This system has an advantage in that only one hand shake line is used without employing a complex communication protocol.

Fourth Embodiment

In the third embodiment of FIG. 3, the operation of the lens CPU 40 is disabled by the image stabilization CPU 37 shown in FIG. 4. However, the control relationship of FIG. 4 may be reversed as in the relationship between the first and second embodiments.

The reversed relationship is realized in a fourth embodiment. A camera hardware arrangement of the fourth embodiment is shown in FIG. 7. The hardware arrangement of the fourth embodiment of FIG. 7 is substantially the same as that of FIG. 4 except that a lens CPU 40 is not connected to an image stabilization CPU 37.

An operation of the fourth embodiment will be described below.

Image stabilization and automatic focus adjusting operations in a centering disable state will be described